Display device and manufacturing method thereof

ABSTRACT

A display device includes a first insulating substrate including a display area, a peripheral area and a test area, a gate conductor including a test element group gate electrode, a gate electrode and a gate line on the first insulating substrate, a gate insulating layer on the gate conductor, a semiconductor layer including a test element group semiconductor layer and a pixel semiconductor layer on the gate insulating layer, a data conductor including a test element group source electrode, a test element group drain electrode, a data line including a source electrode, and a drain electrode on the semiconductor layer, a first passivation layer on the data conductor, a test element group common electrode and a pixel common electrode on the first passivation layer, a second passivation layer on the test element group common electrode and the pixel common electrode, and a pixel electrode on the second passivation layer.

This application claims priority to Korean Patent Application No.10-2013-0151802 filed on Dec. 6, 2013, and all the benefits accruingtherefrom under 35 U.S.C. §119, the entire contents of which areincorporated herein by reference.

BACKGROUND

(a) Field

The invention relates to a display device and a manufacturing methodthereof.

(b) Description of the Related Art

As a display device, a flat panel display may be used. The flat paneldisplay includes a liquid crystal display (“LCD”), an organic lightemitting diode display (“OLED”), a plasma display, an electrophoreticdisplay, and an electrowetting display, for example.

Among the various flat panel displays, an LCD is one of the flat paneldisplays which have been most widely used and generally includes twosheets of display panels in which field generating electrodes, such as apixel electrode and a common electrode, are formed and a liquid crystallayer interposed therebetween. The LCD further includes a backlight unitwhich provides light to the display panels having the liquid crystallayer interposed therebetween. The LCD displays an image by applying avoltage to the field generating electrode to generate an electric fieldin the liquid crystal layer, determining an orientation of liquidcrystal molecules of the liquid crystal layer based on the generatedelectric field, and controlling emission of light provided by thebacklight unit.

Generally, the display device including the LCD includes a thin filmtransistor (“TFT”) array panel. The TFT array panel includes a gateelectrode which is a portion of a gate wire, a semiconductor layerproviding a channel, and a source electrode which is a portion of a datawire and a drain electrode. A TFT is a switching element which transfersor blocks an image signal transferred through the data wire to or fromthe pixel electrode depending on a scanning signal transferred throughthe gate wire.

To confirm whether progress results of each of the processes in aprocess of manufacturing a display device are correct, a thickness,resistance, a concentration, a pollution level, and a critical dimensionof results of each process, electrical characteristics of elements, andthe like are measured. Since it is likely to damage elements during themeasuring process, there is a case in which an actual substrate may notbe monitored during the process.

In this case, a pattern called a test element group (“TEG”) is formed ina specific portion of the substrate on which the elements are formed ora separate test area to perform processes on the substrate on which theactual elements are formed and measure the TEG, thereby evaluating thecorresponding processes and the characteristics of the elements.

SUMMARY

The invention has been made in an effort to provide a display device anda manufacturing method thereof capable of evaluating characteristics ofelements included in the display device without disassembling thedisplay device by improving performance and reliability of a testelement group (“TEG”) element evaluating characteristics of elements.

An exemplary embodiment of the invention provides a display device,including a first insulating substrate including a display area, aperipheral area, and a test area, a gate conductor including a TEG gateelectrode, a gate electrode, and a gate line which are disposed on thefirst insulating substrate, a gate insulating layer disposed on the gateconductor, a semiconductor layer including a TEG semiconductor layer anda pixel semiconductor layer which are disposed on the gate insulatinglayer, a data conductor including a TEG source electrode, a TEG drainelectrode, a source electrode, a drain electrode, and a data line whichare disposed on the semiconductor layer, a first passivation layerdisposed on the data conductor, a TEG common electrode and a pixelcommon electrode which are disposed on the first passivation layer, asecond passivation layer disposed on the TEG common electrode and thepixel common electrode, and a pixel electrode disposed on the secondpassivation layer.

In an exemplary embodiment, the gate electrode, the pixel semiconductorlayer, the source electrode, and the drain electrode may provide a pixelthin film transistor (“TFT”), the TEG gate electrode, the TEGsemiconductor layer, the TEG source electrode, and the TEG drainelectrode may provide a TEG thin film transistor (“TFT”), and the TEGTFT and the TEG common electrode may provide a TEG pattern.

In an exemplary embodiment, the pixel TFT may be located in the displayarea which displays an image and the TEG TFT may be located in the testarea which is located around the display area.

In an exemplary embodiment, the TEG pattern may be provided in pluraland the plurality of TEG patterns may be connected to each other througha TEG connection part which connects neighboring TEG common electrodesof the TEG pattern.

In an exemplary embodiment, the gate conductor may further include acommon voltage line and the pixel common electrode and the TEG commonelectrode may be electrically connected to the common voltage line.

In an exemplary embodiment, the display device may further include amain connection part connecting the pixel common electrode to the TEGcommon electrode.

In an exemplary embodiment, the display device may further include abridge disposed on the second passivation layer, in which the bridge maycontact the TEG common electrode and the common voltage line.

In an exemplary embodiment, the display device may further include afirst alignment layer disposed on the pixel electrode, in which thefirst alignment layer includes a rubbed portion.

In an exemplary embodiment, the display device may further include aseparation line between the test area in which the TEG TFT is locatedand the peripheral area, at which the test area is removed to maintain aportion of the main connection part connecting the TEG common electrodeto the display area or the peripheral area may remain.

Another exemplary embodiment of the invention provides a manufacturingmethod of a display device, including providing a gate conductorincluding a gate electrode, a TEG gate electrode, and a gate line on afirst insulating substrate including a display area, a peripheral area,and a test area, stacking a gate insulating layer on the gate conductor,providing a TEG semiconductor layer and a pixel semiconductor layer onthe gate insulating layer, providing a data conductor including a TEGsource electrode, a TEG drain electrode, a source electrode, a drainelectrode, and a data line on the TEG semiconductor layer and the pixelsemiconductor layer, stacking a first passivation layer on the dataconductor, providing a TEG common electrode and a pixel common electrodeon the first passivation layer, stacking a second passivation layer onthe TEG common electrode and the pixel common electrode, and providing apixel electrode on the second passivation layer.

In an exemplary embodiment, the TEG gate electrode, the TEGsemiconductor layer, the TEG source electrode, and the TEG drainelectrode may provide a TEG TFT, the gate electrode, the pixelsemiconductor layer, the source electrode, and the drain electrode mayprovide a pixel TFT, and the TEG TFT and the TEG common electrode mayprovide a TEG pattern, and the TEG pattern may be provided in plural.

In an exemplary embodiment, the plurality of TEG patterns may beconnected to each other through a TEG connection part which connects theneighboring TEG common electrodes.

In an exemplary embodiment, the manufacturing method of a display devicemay further include providing a main connection part connecting thepixel common electrode to the TEG common electrode.

In an exemplary embodiment, the gate conductor may be provided tofurther include a common voltage line and the pixel common electrode andthe TEG common electrode may be electrically connected to the commonvoltage line.

In an exemplary embodiment, a bridge is further provided in theproviding the pixel electrode, in which the bridge may contact the TEGcommon electrode and the common voltage line.

In an exemplary embodiment, the plurality of TEG patterns may be spacedapart from each other at a predetermined distance.

In an exemplary embodiment, the manufacturing method of a display devicemay further include removing the test area at a separation line betweenthe test area and the peripheral area where the pixel TFT may be locatedin the display area which displays an image and the TEG pattern may belocated in the test area which is disposed around the display area andthe test area may be removed.

In an exemplary embodiment, in the removing the test area, a portion ofthe main connection part connecting the TEG common electrode to thedisplay area or the peripheral area may remain.

In an exemplary embodiment, the manufacturing method of a display devicemay further include applying and rubbing an alignment layer on the pixelelectrode.

In an exemplary embodiment, the providing a TEG semiconductor layer anda pixel semiconductor layer on the gate insulating layer and theproviding a data conductor including a TEG source electrode, a TEG drainelectrode, a source electrode, a drain electrode, and a data line on theTEG semiconductor layer and the pixel semiconductor layer may beperformed using a single mask.

According to the display device as described above, it is possible toevaluate the characteristics of the elements after the rubbing of theliquid crystal without disassembling the display device. Therefore, itis possible to provide the display device including the elements withthe improved reliability and effectively reduce the time and costsrequired to evaluate the display device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other exemplary embodiments, advantages and features ofthis disclosure will become more apparent by describing in furtherdetail exemplary embodiments thereof with reference to the accompanyingdrawings, in which:

FIG. 1 is a conceptual view of an exemplary embodiment of a displaydevice according to the invention.

FIG. 2 is a cross-sectional view of an exemplary embodiment of a testelement group (“TEG”) thin film transistor (“TFT”) according to theinvention.

FIG. 3 is an enlarged view of the exemplary embodiment of a portion ofthe display device according to the invention.

FIG. 4 is a plan view of the exemplary embodiment of one pixel of thedisplay device according to the invention.

FIG. 5 is a cross-sectional view of the display device taken along lineIV-IV of FIG. 4.

FIG. 6 is a cross-sectional view of the display device taken along lineV-V of FIG. 4.

FIG. 7 is a cross-sectional view of the display device taken along lineVI-VI of FIG. 4.

FIG. 8 is an enlarged view of another exemplary embodiment of a portionof a display device according to the invention.

FIG. 9 is a cross-sectional view of the display device taken along lineIX-IX of FIG. 8.

FIGS. 10A to 10D are experimental graphs of a comparative example.

FIG. 11 is an experimental graph of the exemplary embodiment of elementperformance according to the invention.

DETAILED DESCRIPTION

The invention will be described more fully hereinafter with reference tothe accompanying drawings, in which exemplary embodiments of theinvention are shown. As those skilled in the art would realize, thedescribed exemplary embodiments may be modified in various differentways, all without departing from the spirit or scope of the invention.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element orintervening elements may also be present. In contrast, when an elementis referred to as being “directly on” another element, there are nointervening elements present.

Throughout this specification and the claims that follow, when it isdescribed that an element is “coupled” to another element, the elementmay be “directly coupled” to the other element or “electrically coupled”to the other element through a third element. In addition, unlessexplicitly described to the contrary, the word “comprise” and variationssuch as “comprises” or “comprising” will be understood to imply theinclusion of stated elements but not the exclusion of any otherelements.

It will be understood that, although the terms “first,” “second,”“third” etc. may be used herein to describe various elements,components, regions, layers and/or sections, these elements, components,regions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one element, component, region,layer or section from another element, component, region, layer orsection. Thus, “a first element,” “component,” “region,” “layer” or“section” discussed below could be termed a second element, component,region, layer or section without departing from the teachings herein.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “Or” means “and/or.” As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10%, 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

First, a display device according to an exemplary embodiment of theinvention will be described with reference to FIGS. 1 to 7. FIG. 1 is aconceptual view of a display device according to an exemplary embodimentof the invention, FIG. 2 is a cross-sectional view taken along lineII-II of FIG. 1, and FIG. 3 is an enlarged view of a portion of thedisplay device according to the exemplary embodiment of the invention.

Referring to FIG. 1, the display device according to the exemplaryembodiment of the invention includes a display area DA displaying animages and a peripheral area PA located around the display area. In thiscase, the display device may further include a test area TA in which aplurality of test element group (“TEG”) pattern parts are provided, inaddition to the peripheral area PA in which a wiring, and the like isprovided. The test area TA may be removed during a manufacturing processof the display device. FIG. 1 illustrates a dotted line between the testarea TA and the peripheral area PA along which a substrate is cut by alaser and the like, to remove the test area TA.

The display area DA is provided with a plurality of gate lines 121 and aplurality of data lines 171 which intersect each other and are insulatedfrom each other. A plurality of pixels PXs may be arranged in a matrixform by a plurality of signal lines including a plurality of gate lines121 and a plurality of data lines 171. However, the invention is notlimited thereto, and the plurality of pixels PXs may not be arranged ina matrix form by the plurality of signal lines including the pluralityof gate lines 121 and the plurality of data lines 171.

The peripheral area PA may be provided with a plurality of signal lines510 which extend from the gate lines 121 and the data lines 171 in thedisplay area DA and the signal lines extended from the gate lines 121 orthe data lines 171 may be connected to a driving unit (not illustrated)in which is located in the peripheral area PA.

A signal controller (not illustrated) generates a gate control signal, adata control signal, and a digital image signal and then transfers thegate control signal to a gate driver and the data control signal and thedigital image signal to a data driver to control the gate driver and thedata driver.

The gate driver is connected to the gate line 121. The gate driverapplies a gate signal including a combination of gate-on voltage Von andgate-off voltage to the gate line 121 depending on the gate controlsignal from the signal controller (not illustrated).

The data driver is connected to the data line 171. The data driverreceives the data control signal and the digital image signal for thepixels PXs of one row from the signal controller and selects a grayvoltage corresponding to each of the digital image signals to convertthe digital image signals into analog data signals and apply theconverted analog data signals to the corresponding data lines 171.

A switching element is turned on when the gate-on voltage Von is appliedto the gate line 121 connected to the switching element, and the datasignal applied to the data line 171 is applied to the correspondingpixel PX through the turned on switching element.

Driving apparatuses, such as the gate and data drivers and the signalcontroller (not illustrated), may be directly mounted in the peripheralarea PA of a display panel in at least one integrated circuit chip ormounted on a flexible printed circuit film (not illustrated) to beattached to the peripheral area PA in a tape carrier package (“TCP”) ormounted on a separate printed circuit board (“PCB”) (not illustrated).

Referring to FIG. 1, the test area TA is provided with at least one TEGpattern 400. In the illustrated exemplary embodiment, the TEG pattern400 is located only at the top and left of the display device, but theinvention is not limited thereto, and the TEG pattern 400 may be removedin at least one of the top, bottom, left, and right portions of thedisplay area DA. In an exemplary embodiment, the TEG pattern 400 may belocated in any area enclosing a circumference of the display area DA.

The TEG pattern 400 may be connected to the driver through a connectionwiring but is not limited thereto, and may be directly connected to thepixel PX, which is located in the display area DA, through a mainconnection part 491.

The plurality of TEG patterns 400 may be located to be spaced apart fromeach other at a predetermined distance and the neighboring TEG patterns400 may be connected to each other through a TEG connection part 492.This will be described below.

The one TEG pattern 400 may include a plurality of TEG thin filmtransistors (“TFTs”) 410 (refer to FIG. 3) and may be provided alongwith a manufacturing process of a pixel TFT which is located in thedisplay area, such that the TEG pattern 400 may serve to evaluateperformance of the pixel TFT. That is, instead of the pixel TFT which islocated in the display area DA, the TEG TFT 410 of the TEG pattern 400which is located in the test area TA may be evaluated. By doing so, itis possible to provide the display device having more excellentperformance and characteristics and it is possible to evaluate theperformance and characteristics of the display device with a simpleprocess and low cost.

FIG. 2 illustrates a cross section of the one TEG TFT included in theTEG pattern 400 illustrated in FIG. 1.

The TEG TFT includes a plurality of TEG gate electrodes 126 providedsimultaneously with a gate conductor on a first insulating substrate110.

A gate insulating layer 140 is disposed on the TEG gate electrode 126.In an exemplary embodiment, the gate insulating layer 140 may includeinorganic insulating materials, and the like, such as silicon nitride(SiNx) and silicon oxide (SiOx).

A plurality of TEG semiconductor layers 156 is disposed on the gateinsulating layer 140. In an exemplary embodiment, the TEG semiconductorlayer 156 may be disposed only on the TEG gate electrode 126. In thiscase, the TEG semiconductor layer 156 may include a material includingan oxide semiconductor.

A plurality of ohmic contacts (refer to FIG. 5) may be disposed on theTEG semiconductor layer 156. In an exemplary embodiment, the ohmiccontacts may be provided as a pair, facing each other with reference tothe TEG gate electrode 126 and disposed on the TEG semiconductor layer156. In an exemplary embodiment, the ohmic contact may include amaterial such as n+ hydrogenated amorphous silicon doped withhigh-concentration n-type impurity such as phosphorous or may includesilicide. However, when the TEG semiconductor layer 156 includes theoxide semiconductor, the ohmic contact may be omitted.

The data conductor including a plurality of TEG source electrodes 176and a plurality of TEG drain electrodes 177 is disposed on the TEGsemiconductor layer 156. In an exemplary embodiment, the TEG drainelectrode 177 may include a bar-shaped end facing the TEG sourceelectrode 176 with reference to the TEG gate electrode 126 and the otherend with a wide area, but is not limited thereto.

The TEG gate electrode 126, the TEG source electrode 176, and the TEGdrain electrode 177 provide a TEG TFT which is a switching element,along with the TEG semiconductor layer 156. The semiconductor layer 156may have substantially the same plane shape with the TEG drain electrode177 and the ohmic contact which is disposed under the TEG drainelectrode 177, except for the area in which the TEG TFT is disposed.

A first passivation layer 180 x is disposed on the data conductors 176and 177 and the exposed TEG semiconductor layer 156, and may include anorganic insulating material, an inorganic insulating material, or thelike.

Further, referring to FIG. 2, an organic insulating layer 80 may bedisposed on the first passivation layer 180 x, but the invention is notlimited thereto, and the organic insulating layer 80 may be omitted inanother exemplary embodiment of the invention.

A plurality of TEG common electrodes 276 is disposed on the organicinsulating layer 80. The TEG common electrode 276 may includetransparent conductive materials, such as indium tin oxide (“ITO”) andindium zinc oxide (“IZO”), for example. The TEG common electrode 276 ofa planar type is disposed on the whole plane of the TEG pattern 400 andmay cover the plurality of TEG TFTs included in the TEG pattern 400.

As described above, the plurality of TEG TFTs 410 and TEG commonelectrodes 276 provide one TEG pattern 400. In an exemplary embodiment,the TEG pattern 400 may be provided in plural, spaced apart from eachother at a predetermined distance as illustrated in FIG. 1.

As described above, the TEG pattern 400 is provided by the same processas the process which is applied to the TFT and the like within the pixelprovided in the display area DA.

Referring to FIG. 3, the one TEG pattern 400 includes the plurality ofTEG TFTs 410 and includes one TEG common electrode 276 to cover theplurality of TEG TFTs 410.

The plurality of TEG patterns 400 may be connected to each other by aTEG connection part 492. In particular, the TEG connection part 492 mayconnect between the TEG common electrodes 276 included in each of theTEG patterns 400. In this case, the TEG connection part 492 may beprovided along with the TEG common electrode 276. That is, the TEGconnection part 492 may include the same material as the TEG commonelectrode 276 and the TEG connection part 492 and the TEG commonelectrode 276 may be disposed in the same layer.

Further, the pixel common electrode 270 may be disposed in the samelayer as the TEG common electrode 276 and the pixel common electrode 270and the TEG common electrode 276 may be simultaneously provided. Inparticular, the pixel common electrode 270 and the TEG common electrode276 may be connected to each other through the main connection part 491.The main connection part 491 may also be provided along with the pixelcommon electrode 270 and the TEG common electrode 276 and the mainconnection part 491, the pixel common electrode 270, and the TEG commonelectrode 276 may include the same material.

That is, as illustrated in FIG. 3, the main connection part 491 connectsthe pixel common electrode 270 to the TEG common electrode 276 in thesame layer, the pixel common electrode 270 is connected to a commonvoltage line 131 through a contact hole 184 (refer to FIG. 4), and theTEG common electrode 276 may also be electrically connected to thecommon voltage line 131.

A second passivation layer 180 y may be disposed on the TEG commonelectrode 276. The second passivation layer 180 y may include an organicinsulating material, an inorganic insulating material, or the like.Further, a first alignment layer 11 may be disposed on the secondpassivation layer 180 y.

Referring to FIG. 3, the substrate may be cut along the dotted linebetween the test area TA and the peripheral area PA by a laser and thelike, to remove the test area TA. When the test area TA is removed, themain connection part 491 and the TEG pattern 400 located in the testarea are removed and a portion of the main connection part 491 locatedin the display area or the peripheral area may remain in the displaydevice.

The plurality of TEG patterns 400 are provided by the same process asthe process which is applied to the pixel TFT located in the displayarea DA to be described below. In this case, a performance of the pixelTFT included in the display device may be evaluated by evaluating theTEG pattern 400.

In an exemplary embodiment, the TEG pattern 400 includes the TEG commonelectrode 276, thereby preventing a reduction in performance due tostatic electricity which may occur during the process.

Hereinafter, the display area DA of the display device will be describedwith reference to FIGS. 4 to 7. FIG. 4 is a plan view of one pixel ofthe display device according to the exemplary embodiment of theinvention, FIG. 5 is a cross-sectional view of the display device takenalong line IV-IV of FIG. 4, FIG. 6 is a cross-sectional view of thedisplay device taken along line V-V of FIG. 4, and FIG. 7 is across-sectional view of the display device taken along line VI-VI ofFIG. 4.

Referring to FIGS. 4 to 7, the display device according to the exemplaryembodiment of the invention includes a lower display panel 100 and anupper display panel 200 which face each other and a liquid crystal layer3 located between the two display panels 100 and 200.

First, the lower display panel 100 will be described.

The first insulating substrate 110 includes the display area DA, theperipheral area, and the test area. Hereinafter, the pixel TFT elementprovided in the display area DA will be described.

First, a gate conductor including the gate line 121 and the commonvoltage line 131 is disposed on the first insulating substrate 110.

The gate line 121 transfers the gate signal and mainly extends in ahorizontal direction. Each of the gate lines 121 includes a plurality ofgate electrodes 124. Further, the gate line 121 has a wide area andfurther includes a gate pad part (not illustrated) contacting an ohmiccontact to transfer the signal to the gate line 121.

The common voltage line 131 extends in parallel with the gate line 121and includes an extension 133.

The gate insulating layer 140 is disposed on the gate line 121 and thecommon voltage line 131. The gate insulating layer 140 may include aninorganic insulating material, such as silicon nitride (SiNx) andsilicon oxide (SiOx).

A plurality of pixel semiconductor layers 151 and 154 is disposed on thegate insulating layer 140. In another exemplary embodiment, the pixelsemiconductor layer 154 may be disposed only on the gate electrode 124.In an exemplary embodiment, the pixel semiconductor layers 151 and 154may include an oxide semiconductor.

The plurality of ohmic contacts 161, 163 and 165 may be disposed on thepixel semiconductor layer 154. The ohmic contacts 163 and 165 areprovided as a pair, facing each other based on the gate electrode 124and are disposed on the pixel semiconductor layer 154. The ohmiccontacts 161, 163 and 165 may include a material such as n+ hydrogenatedamorphous silicon doped with high-concentration n-type impurity such asphosphorous or may include silicide. However, when the pixelsemiconductor layer 154 includes the oxide semiconductor, the ohmiccontacts may be omitted.

The data conductor including the plurality of data lines 171 and theplurality of drain electrodes 175 is disposed on the pixel semiconductorlayer 154.

The data line 171 transfers a data signal and mainly extends in avertical direction in a plan view to intersect the gate line 121. Thedata conductor includes a plurality of source electrodes 173 whichextend toward the gate electrode 124. In an exemplary embodiment, thedata line 171 may extend straightly. However, the invention is notlimited thereto, and the data line 171 may be periodically bent with anoblique angle with respect to an extending direction of the gate line121. In an exemplary embodiment, the oblique angle of the data line 171with respect to the extending direction of the gate line 121 may beequal to or larger than about 45 degrees (°), for example.

The drain electrode 175 includes a bar-shaped end facing the sourceelectrode 173 with reference to the gate electrode 124 and the other endhaving a wide area.

The gate electrode 124, the source electrode 173, and the drainelectrode 175 provide the pixel TFT which is the switching element,along with the pixel semiconductor layer 154. A linear semiconductorlayer 154 may have substantially the same plane shape with the data line171, the drain electrode 175 and the ohmic contact 165 under the drainelectrode 175, except for the pixel semiconductor layer protrusion 154in which the TFT is located.

The first passivation layer 180 x is disposed on the data conductors 171and 175 and the exposed pixel semiconductor layer 154, and may includean organic insulating material, an inorganic insulating material, or thelike.

An organic insulating layer 80 may be disposed on the first passivationlayer 180 x, but the invention is not limited thereto, and the organicinsulating layer 80 may be omitted in another exemplary embodiment ofthe invention

The plurality of pixel common electrodes 270 is disposed on the firstpassivation layer 180 x. In an exemplary embodiment, the pixel commonelectrode 270 may include the transparent conductive materials, such asITO and IZO, for example. The pixel common electrode 270 which is aplanar type may be disposed on the whole surface of the substrate 110 inan integrated plate, and an opening 273 which is located in an areacorresponding to the circumference of the drain electrode 175 may bedefined in the pixel common electrode 270.

A first contact hole 184 (refer to FIG. 4 and FIG. 7) through which theextension 133 of the common voltage line 131 is exposed is defined inthe gate insulating layer 140 and the first passivation layer 180 x.

The pixel common electrode 270 may be physically and electricallyconnected to the common voltage line 131 through the first contact hole184.

In this case, the pixel common electrode 270 is provided simultaneouslywith the TEG common electrode 276 (refer to FIG. 3), and the pixelcommon electrode 270 may be connected to the TEG common electrode 276through the main connection part 491 (refer to FIG. 3). The mainconnection part 491 may also be provided along with the pixel commonelectrode 270 and the TEG common electrode 276.

That is, the main connection part 491 connects the pixel commonelectrode 270 to the TEG common electrode 276 as illustrated in FIG. 3,the pixel common electrode 270 is connected to the common voltage line131 through the contact hole 184 as illustrated in FIG. 4, thereby theTEG common electrode 276 may also be electrically connected to thecommon voltage line 131 via the main connection part 491.

However, the invention is not limited thereto, but according to anotherexemplary embodiment of the invention, the TEG common electrode 276 maybe connected to the common voltage line 131 through a bridge 196. Thiswill be described below referring to FIG. 8.

The second passivation layer 180 y is disposed on the pixel commonelectrode 270. The second passivation layer 180 y may include an organicinsulating material, an inorganic insulating material, or the like.

A pixel electrode 191 is disposed on the second passivation layer 180 y.The pixel electrode 191 includes a plurality of first branch electrodes193 which generally extend in parallel with each other and are spacedapart from each other, and lower and upper horizontal parts 192 whichconnect upper and lower ends of the plurality of first branch electrodes193. The first branch electrode 193 of the pixel electrode 191 may bebent along the data conductor. However, the invention is not limitedthereto, and the data conductor and the first branch electrode 193 ofthe pixel electrode 191 may extend straightly in another exemplaryembodiment. In an exemplary embodiment, the pixel electrode 191 mayinclude transparent conductive materials, such as ITO and IZO, forexample.

A plurality of second contact holes 183 through which a portion of thedrain electrode 175 is exposed is defined in the first passivation layer180 x and the second passivation layer 180 y, and the pixel electrode191 is electrically connected to the drain electrode 175 through thesecond contact hole 183 to be applied with a data voltage. The pixelelectrode 191 applied with the data voltage generates an electric fieldin the liquid crystal layer 3, along with the pixel common electrode 270applied with the common voltage.

The first branch electrode 193 of the pixel electrode 191 overlaps thepixel common electrode 270 of a planar type.

The first alignment layer 11 is applied on an inside of the lowerdisplay panel 100 and may be hardened and rubbed. Predetermined staticelectricity may occur during the rubbing process.

Next, the upper display panel 200 will be described.

A light blocking member 220 is disposed on a second insulating substrate210 including transparent glass, plastic, or the like. The lightblocking member 220 is also referred to as a black matrix and preventslight from leaking.

Further, a plurality of color filters 230 is disposed on the secondinsulating substrate 210.

An overcoat 250 is disposed on the color filter 230 and the lightblocking member 220. The overcoat 250 may include an (organic)insulating material and prevents the color filter 230 from being exposedand provides a flat surface. The overcoat 250 may be omitted.

A second alignment layer 21 may be disposed on the overcoat 250. Thefirst alignment layer 11 and the second alignment layer 21 may be ahorizontal alignment layer.

The liquid crystal layer 3 interposed between the lower display panel100 and the upper display panel 200 includes a liquid crystal molecule(not illustrated), in which the liquid crystal molecule may be alignedso that a major axis thereof is horizontal to surfaces of the twodisplay panels 100 and 200 in a state in which no electric field ispresent.

An outside of the substrate 110 of the lower display panel 100 may befurther provided with a light unit (not illustrated) which generateslight and provides the light to the two display panels 100 and 200.

The pixel electrode 191 applied with the data voltage generates anelectric field in the liquid crystal layer 3 along with the pixel commonelectrode 270 applied with the common voltage, thereby determining theorientation of the liquid crystal molecule of the liquid crystal layer 3and displaying the corresponding image.

The peripheral area in which the TEG TFT 410 is provided, in particular,the test area may be removed by the manufacturing process of the displaydevice. When the test area is removed, the TEG pattern 400 is alsoremoved. In this case, a portion of the main connection part 491connecting the TEG common electrode 276 to the pixel common electrode270 may remain on the substrate, and for example, the bridge 196 (referto FIG. 8) may remain thereon.

As described above, the pixel TFT and the TEG TFT located in the displayarea DA and the test area TA may be simultaneously provided by the sameprocess and to evaluate the performance and characteristics of the pixelTFT located in the display area DA, the TEG TFT element provided in theTEG pattern may be evaluated. By doing so, the performance andcharacteristics of the element may be evaluated without affecting thedisplay area DA. In particular, since the TEG pattern including the TEGcommon electrode is not affected by static electricity, and the like,the TEG pattern may be reliably evaluated after the rubbing of thealignment layer in which the static electricity may occur.

The exemplary embodiment of the invention as described above describesthat any one of the pixel electrode and the common electrode has a plateshape and the other includes the plurality of branch electrodes, but theinvention is not limited thereto and therefore may be applied to allother types of liquid crystal displays in which the pixel electrode andthe common electrode are disposed on one substrate.

Further, the exemplary embodiment of the invention as described abovedescribes the liquid crystal display (“LCD”) in which the pixelelectrode and the common electrode overlap each other, having theinsulating layer therebetween, but the invention is not limited thereto,and therefore may be applied to all other types of liquid crystaldisplays in which the pixel electrode and the common electrode aredisposed on one substrate.

The manufacturing method of the display device according to theexemplary embodiment of the invention will be described with referenceto FIGS. 1 to 7 described above.

First, the metal layer is stacked on the first insulating substrate 110and the gate conductor including the common voltage line 131, the TEGgate electrode 126, the gate electrode 124, and the gate line 121 isprovided by a photolithography process.

According to the exemplary embodiment of the invention, the gate wire isprovided in a single layer, but the invention is not limited thereto,and the gate wire may be provided in a double layer. In this case, thelower metal layer may include any one selected from aluminum (Al) andaluminum neodymium (AlNd) and the upper metal layer may includemolybdenum (Mo), for example.

Next, the gate insulating layer 140 is disposed on the gate conductor bya chemical vapor deposition (“CVD”) method. In this case, for example,silane gas (SiH₄), hydrogen gas (H₂), nitrogen gas (NH₃), and the likeare supplied inside a CVD chamber providing the gate insulating layer140.

Next, source gas including SiF₄ gas, SiH₄ gas, and the like is suppliedinside the CVD chamber to provide the TEG semiconductor layer 156 andthe pixel semiconductor layer 154.

Next, a conductive layer is stacked and the data conductor including thedata line 171, the source electrode 173, the drain electrode 175, theTEG source electrode 176, and the TEG data electrode 177 is provided bythe photolithography process. The drain electrode 175 and the TEG drainelectrode 177 are each spaced apart from the source electrode 173 andthe TEG source electrode 176, and are located on the upper portion of anopposite side of the source electrode 173 and the TEG source electrode176 based on the gate electrode 124 and the TEG gate electrode 126.

In this case, the providing the TEG semiconductor layer 156 and thepixel semiconductor layer 154 and the providing the data conductorincluding the TEG source electrode, the TEG drain electrode, the sourceelectrode, the drain electrode, and the data line may be performed usingone mask.

Next, the first passivation layer 180 x and the organic insulating layer80 are provided to cover the exposed semiconductor layers 154 and 156and then the common electrode conductor is stacked.

The pixel common electrode 270 is provided in the display area DA andthe TEG common electrode 276 is provided in the test region, by etchingthe stacked common electrode conductor. In this case, as illustrated inFIG. 3, the TEG connection part 492 connecting between the neighboringTEG common electrodes 276 and the main connection part 491 connectingthe pixel common electrode 270 to the TEG common electrode 276 may beprovided.

The pixel common electrode 270 may contact the common voltage line 131through the contact hole 184, and the TEG common electrode 276 connectedto the pixel common electrode 270 may be electrically connected to thecommon voltage line 131.

According to another exemplary embodiment of the invention, the TEGcommon electrode 276 may be electrically connected to the common voltageline 131 through a bridge 196 provided simultaneously with the pixelelectrode 191. This will be described below.

Next, the second passivation layer 180 y and the pixel electrode 191 areprovided and the first alignment layer 11 may be provided by applying,hardening, and rubbing the alignment layer on the pixel electrode 191.

The gate electrode 124, the source electrode 173, and the drainelectrode 175 which are located in the display area DA provide the pixelTFT along with the pixel semiconductor layer 154. In addition, the TEGgate electrode 126, the TEG source electrode 176, and the TEG drainelectrode 177 which are located in the peripheral area provide the TEGTFT 410 along with the TEG semiconductor layer 156 and the plurality ofTEG TFTs 410 provide the TEG pattern 400 along with the TEG commonelectrode 276.

According to the exemplary embodiment of the invention, the TEG pattern400 may be provided in plural, and the plurality of TEG patterns 400 isspaced apart from each other at a predetermined distance.

The TEG pattern 400 is provided in the test area TA and the test area TAmay be removed during the manufacturing process of the display device.Therefore, when the test area including the TEG pattern 400 is removed,a portion of the main connection part 491 connecting the pixel commonelectrode 270 to the TEG common electrode 276 may remain in the displaydevice. In another example, the bridge 196 may remain in the displaydevice.

The TEG TFT manufactured by the manufacturing method as described aboveis not affected by static electricity occurring by the rubbing processof the alignment layer and thus may be appropriate to evaluate theperformance of the pixel TFT located in the display area DA.

The display device according to another exemplary embodiment of theinvention will be described in detail with reference to FIGS. 8 and 9.FIG. 8 is an enlarged view of a part of a display device according toanother exemplary embodiment of the invention and FIG. 9 is across-sectional view of the display device taken along line IX-IX ofFIG. 8. The description of the same or similar components as or to theforegoing components will be omitted.

According to another exemplary embodiment of the invention, the pixelcommon electrode 270 and the TEG common electrode 276 may beelectrically connected through the bridge 196 provided simultaneouslywith the pixel electrode 191.

According to the exemplary embodiment of the invention, the pixel commonelectrode 270 and the TEG common electrode 276 are physically connectedto each other through the main connection part 491 providedsimultaneously with the pixel common electrode 270 and the TEG commonelectrode 276, but according to another exemplary embodiment of theinvention, the pixel common electrode 270 and the TEG common electrode276 are electrically connected to each other through another mainconnection part simultaneously provided with the pixel electrode 191,that is, the bridge 196.

Referring to in detail FIGS. 8 and 9, the second passivation layer 180 yis disposed on the pixel common electrode 270 the TEG common electrode276.

Next, the pixel electrode 191 is disposed on the second passivationlayer 180 y. In this case, the bridge 196 is provided simultaneouslywith the pixel electrode 191. The bridge 196 contacts the TEG commonelectrode 276 through the contact hole of the second passivation layer180 y and contacts the pad part 139 through the contact hole providingthe opening for the pad part 139 of the common voltage line.

That is, the TEG common electrode 276 may be electrically connected tothe pad part 139 of the common voltage line 131 through the bridge 196and the pixel common electrode 270 is electrically connected to theextension 133 of the common voltage line through the opening. Therefore,the TEG common electrode 276 and the pixel common electrode 270 may beelectrically connected to each other.

In the display device according to the exemplary embodiment of theinvention, the TEG common electrode 276 is directly connected to thepixel common electrode 270 and thus electrically connected to the commonvoltage line 131, and in the display device according to anotherexemplary embodiment of the invention, the TEG common electrode 276 isconnected to the pad part 139 of the common voltage line through thebridge 196 and the pixel common electrode 270 contacts the extension 133of the common voltage line and thus may be electrically connected to theextension 133.

Referring to FIG. 8, the substrate may be cut along a dotted linebetween the test area TA and the peripheral area PA by a laser, and thelike to be able to remove the test area TA. When the test area TA isremoved, the bridge 196 and the TEG pattern 400 located in the test areaare removed and a portion of the bridge 196 located in the peripheralarea may remain in the display device.

Hereinafter, effects of the exemplary embodiment of the invention willbe described with reference to FIGS. 10A to 10D and 11. FIGS. 10A to 10Dare experimental graphs of a comparative example which does not includethe TEG common electrode, and FIG. 11 is a graph of element performance.Referring to FIGS. 10A to 10D and 11, y-axis represents a drain-sourcecurrent Ids measured in ampere (A) and x-axis represents a gate voltagemeasured in volt (V).

FIG. 10A is a graph of the performance evaluation of the TFT performedafter the TEG TFT which is a comparative example is provided. It can beappreciated from FIG. 10A that each of the TEG TFTs has substantiallythe constant threshold voltage value.

FIG. 10B is a graph of the performance evaluation of the TFT performedafter the alignment layer is applied on the TEG TFT which is acomparative example, and FIG. 10C is a graph of the performanceevaluation of the TFT performed after the alignment layer is applied andhardened. Referring to FIGS. 10B and 10C, it is shown that each of theTEG TFTs has substantially the constant threshold voltage value.

Next, FIG. 10D is a graph of the performance evaluation of the TEG TFTperformed after the alignment layer is hardened and the rubbing processis performed. Referring to FIG. 10D, it is shown that after the rubbingprocess is performed, the threshold voltage value of the TFT moves to apositive side and the scattering of the voltage value is alsoconsiderably increased.

However, describing the characteristics evaluation of the TFT includingthe common electrode which undergoes the same process as FIG. 10D withreference to FIG. 11, it may be appreciated that even after thealignment layer is rubbed, the characteristics of the TFT are littlechanged.

That is, it can be appreciated that the TEG TFT which is provided by thesame process as the pixel TFT located in the display area and providedin the test area to evaluate the performance of the pixel TFT indicatesthe constant characteristics even after the alignment layer is rubbed asthe TEG pattern includes the TEG common electrode.

As a result, it is possible to evaluate the performance of the pixel TFTwith the TEG TFT located in the test area, and in particular, it ispossible to evaluate the performance even after the alignment layer isprovided. Further, since the reliability of the performance evaluationis improved, it is possible to provide the excellent display device.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosed exemplaryembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A display device, comprising: a first insulatingsubstrate including a display area, a peripheral area, and a test area;a gate conductor including a test element group gate electrode, a gateelectrode, and a gate line which are disposed on the first insulatingsubstrate; a gate insulating layer disposed on the gate conductor; asemiconductor layer including a test element group semiconductor layerand a pixel semiconductor layer which are disposed on the gateinsulating layer; a data conductor including a test element group sourceelectrode, a test element group drain electrode, a data line including asource electrode, and a drain electrode which are disposed on thesemiconductor layer; a first passivation layer disposed on the dataconductor; a test element group common electrode and a pixel commonelectrode which are disposed on the first passivation layer; a secondpassivation layer disposed on the test element group common electrodeand the pixel common electrode; and a pixel electrode disposed on thesecond passivation layer.
 2. The display device of claim 1, wherein: thegate electrode, the pixel semiconductor layer, the source electrode, andthe drain electrode provide a pixel thin film transistor, the testelement group gate electrode, the test element group semiconductorlayer, the test element group source electrode, and the test elementgroup drain electrode provide a test element group thin film transistor,and the test element group thin film transistor and the test elementgroup common electrode provide a test element group pattern.
 3. Thedisplay device of claim 2, wherein: the pixel thin film transistor islocated in the display area which displays an image, and the testelement group thin film transistor is located in the test area which islocated around the display area.
 4. The display device of claim 2,further comprising a plurality of test element group patterns, andwherein the plurality of test element group patterns is connected toeach other through a test element group connection part which connectsneighboring test element group common electrodes of the plurality oftest element group patterns.
 5. The display device of claim 4, wherein:the gate conductor further includes a common voltage line, and the pixelcommon electrode and the test element group common electrode areelectrically connected to the common voltage line.
 6. The display deviceof claim 5, further comprising: a main connection part connecting thepixel common electrode to the test element group common electrode. 7.The display device of claim 5, further comprising: a bridge disposed onthe second passivation layer, wherein the bridge contacts the testelement group common electrode and the common voltage line.
 8. Thedisplay device of claim 1, further comprising: a first alignment layerdisposed on the pixel electrode, wherein the first alignment layerincludes a rubbed portion.
 9. The display device of claim 6, furthercomprising a separation line between the test area in which the testelement group thin film transistor is located and the peripheral area,and at which the test area is removed to maintain a portion of the mainconnection part connecting the TEG common electrode to the display areaor the peripheral area.
 10. A manufacturing method of a display device,the method comprising: providing a gate conductor including a gateelectrode, a test element group gate electrode, and a gate line on afirst insulating substrate including a display area, a peripheral area,and a test area; disposing a gate insulating layer on the gateconductor; disposing a test element group semiconductor layer and apixel semiconductor layer on the gate insulating layer; disposing a dataconductor including a test element group source electrode, a testelement group drain electrode, a source electrode, a drain electrode,and a data line on the test element group semiconductor layer and thepixel semiconductor layer; disposing a first passivation layer on thedata conductor; disposing a test element group common electrode and apixel common electrode on the first passivation layer; disposing asecond passivation layer on the test element group common electrode andthe pixel common electrode; and disposing a pixel electrode on thesecond passivation layer.
 11. The manufacturing method of claim 10,wherein: the test element group gate electrode, the test element groupsemiconductor layer, the test element group source electrode, and thetest element group drain electrode provide a test element group thinfilm transistor, the gate electrode, the pixel semiconductor layer, thesource electrode, and the drain electrode provide a pixel thin filmtransistor, the test element group thin film transistor and the testelement group common electrode provide a plurality of test element grouppatterns.
 12. The manufacturing method of claim 11, wherein: theplurality of test element group patterns is connected to each otherthrough a test element group connection part which connects neighboringtest element group common electrodes of the plurality of test elementgroup patterns.
 13. The manufacturing method of claim 10, furthercomprising: providing a main connection part connecting the pixel commonelectrode to the test element group common electrode.
 14. Themanufacturing method of claim 13, wherein: the gate conductor furtherincludes a common voltage line, and the pixel common electrode and thetest element group common electrode are electrically connected to thecommon voltage line.
 15. The manufacturing method of claim 14, wherein abridge is further provided in the providing the pixel electrode, and thebridge contacts the test element group common electrode and the commonvoltage line.
 16. The manufacturing method of claim 11, wherein: theplurality of test element group patterns is spaced apart from each otherat a predetermined distance.
 17. The manufacturing method of claim 11,further comprising removing the test area at a separation line betweenthe test area and the peripheral area, wherein the pixel thin filmtransistor is located in the display area which displays an image, andthe test element group pattern is located in the test area which isdisposed around the display area.
 18. The manufacturing method of claim17, wherein: in the removing the test area, a portion of the mainconnection part connecting the test element group common electrode tothe display area or the peripheral area remains.
 19. The manufacturingmethod of claim 10, further comprising: applying and rubbing analignment layer on the pixel electrode.
 20. The manufacturing method ofclaim 10, wherein: the providing the data conductor including the testelement group source electrode, the test element group drain electrode,the source electrode, the drain electrode, and the data line on the testelement group semiconductor layer and the pixel semiconductor layer isperformed using a single mask.